1. Field of Invention
The present invention relates to an image processing method, and particularly to a method for rendering multi-dimensional image data.
2. Description of the Related Art
The progress in science and technology has introduced computers into new broader applications, such as in architecture design roving, virtual reality, animation, and advanced game programming. All of the aforementioned applications require 2-dimensional image processing and 3-dimensional image processing. Indeed, in the modern time, the 2-dimensional and 3-dimensional image rendering technology has played a vital role in widespread applications.
In the U.S. Pat. No. 5,805,135, Sony Corporation in Japan has provided a 2-dimensional and 3-dimensional image rendering method, by which an image data to be displayed is divided into a plurality of objects for forming. Take for example, a background, a 2-D sprite (a 2-D picture of a chair for example; for the sake of simplicity, it is to be termed as a sprite hereinafter), a 3-D ball, and a 3-D cup. In which, a sprite can be an object, while a background can be an object or sprite. Furthermore, a sprite can be formed from a combination of a plurality of sprites. In which, the ball and the cup are formed from a number of polygons, and each polygon is counted as an object. Each of the above-described objects possess a depth value therewith, or a Z value for simplicity.
As the above-described object data are fed into an image processor, the image processor starts to compare one by one each of the Z value. For every object, it needs to compare the Z value of the object with all other Z values of preceding inputted objects, until all of the objects in the image data are inputted and sorted completely, followed by graphic manipulations sequentially from the maximum Z value to the minimum Z value.
From the above description, it can be seen that a conventional rendering method requires continuously uninterrupted comparison of the objects. Such exhaustive computation is wasteful of much of the memory bandwidth and provides a heavy burden on the image processor.